The present invention relates to a hydro-hoist and method of operating the same for conveying a slurry under pressure by a driving liquid and, more particularly, to a vertical hydro-hoist and method for feeding a slurry under pressure by using a liquid obtained from a chemical process as a driving liquid in, for example, coal liquefaction.
In, for example, U.S. Pat. Nos. 4,387,595 and 4,536,131, as well as in Japanese Patent Application Laid Open KOKAI No. 56 145026 (1981) and Japanese Patent Publication No. 48 15163 (1973), it has been proposed to convey a slurry under pressure through a float by a driving liquid after temporarily charging a plurality of feed chambers with the slurry. In construction of the aforementioned type, an adjustment of the specific gravity of the float is effected by a bellows provided at a portion of the float so that an apparent specific gravity of the float is varied according to a magnitude of the pressures of the slurry and the driving liquid.
It has also been proposed to provide an arrangement wherein the specific gravity of the float is adjusted by regulating or controlling a weight provided at a lower portion of the float.
In chemical processes such as, for example, coal liquefaction, a liquefied oil is ordinarily used as a driving liquid, and it is apparent that the specific gravity of the driving liquid depends on the type of coal being processed.
In this connection, in the above described proposals, no consideration has been given to ensuring that the specific gravity of the float can be easily adjusted in accordance with a change in a specific gravity of the driving liquid or the specific gravity of the slurry. Consequently, an adjustment of the float has been carried out by momentarily or temporarily stopping the operation of the entire process of the hydro-hoist, taking out the float from the feed chamber, and regulating the weight provided for the float in accordance with the specific gravity of the driving liquid. Alternatively, several types of floats differing in specific gravity had been prepared to be substituted as required.
Thus, for adjusting a specific gravity of the float, it has been necessary to momentarily or temporarily stop the operation of the hydro-hoist, thereby adversely affecting the overall liquefacation process and, consequently, increasing the operating cost thereof.
The aim underlying the present invention essentially resides in providing a vertical hydro-hoist and method of operating the same wherein a specific gravity of a float can easily be adjusted in accordance with changes in a specific gravity of either a driving liquid or slurry without stopping the operation of the hydro-hoist and, more particularly, without stopping the operation of the overall process.
In accordance with advantageous features of the present invention, a vertical hydro-hoist is proposed which comprises a plurality of feed chambers for momentarily or temporarily reserving a slurry, and supplying discharge pipes for a driving liquid for feeding the slurry under pressure, with the supply and discharge pipes being connected to an upper portion of each of the feed chambers, and with the slurry feed and discharge pipes being connected to a lower portion of each of the feed chambers. Sensors or detectors are provided at upper and lower portions or parts on an outside of the feed chamber for detecting or sensing a position of a float floating at an interface between the slurry and the driving liquid in each of the feed chambers. Valves are provided in the driving liquid supply and discharge pipes and the slurry feed and discharge pipes, with the valves being open and closed in accordance with data received from the detectors to thereby feed the slurry under pressure. A specific gravity detector or sensor is also provided for detecting or sensing the specific gravity of at least one of either the driving liquid or the slurry. Moreover, a device for adjusting the specific gravity of the float is provided and the specific gravity adjusting device includes a holder member for momentarily or temporarily gripping the float. Means are provided for supplying and discharging a specific gravity adjusting liquid into and out of the float, with a controller being provided for the specific gravity adjusting device for adjusting the specific gravity of the float in accordance with a deviation or variation between a preset specific gravity of the float and a specific gravity detected by the specific gravity detector or sensor.
In accordance with further advantageous features of the present invention, a vertical hydro-hoist is proposed which includes feed chambers, supply and discharge pipe means for a driving liquid, slurry feed and discharge pipe means, a float means, a float position detector means, a detector means for detecting a rise and fall of the float means over a predetermined distance, and a means for adjusting the specific gravity of the float means and a controller means. The specific gravity adjusting means includes a holder member for momentarily or temporarily gripping the float means and means for supplying and discharging a specific a specific gravity adjusting liquid into and out of the float means. The controller means controls the specific gravity adjusting means for adjusting the specific gravity of the float means in accordance with the difference between the rise time and the fall time detected or sensed by the detector means.
In accordance with still further features of the present invention, a method for operating a hydro-hoist is proposed, with the hydro-hoist including a plurality of feed chambers for reserving or storing a slurry, supply and discharge pipes means for feeding a driving liquid to the feed chambers, slurry and feed discharge pipe means for feeding slurry to the feed chamber, and a float means provided in the feed chambers, with the method including the steps of detecting a relationship of the specific gravity between the driving liquid, the slurry and the float means, and stopping the operation of at least one of the feed chambers, fixing the float means at a predetermined position in the feed chamber for stopping the operation, adjusting the specific gravity of the float means by supplying or discharging a specific gravity adjusting liquid into or out of the float means in accordance with a detected relationship of the specific gravities, and establishing the following relationship:
SG.sub.L .ltoreq.SG.sub.F .ltoreq.SG.sub.S, PA1 SG.sub.L =the specific gravity of the driving liquid; PA1 SG.sub.F =the specific gravity of the float means; and PA1 SG.sub.S =the specific gravity of the slurry means.
where:
According to still further features of the present invention, the specific gravity of at least one of either the driving liquid or the slurry is detected by detector means and, when the detected specific gravity shows a deviation or variation from a preset or predetermined allowable specific gravity, the operation of at least one feed chamber is stopped and the specific gravity of the float means is adjusted
The rise time and fall time of the float means are detected and, when a difference between the rise time and the fall time exceeds a preset or predetermined allowable value, the operation of least one feed chamber is stopped and the specific gravity of the float is adjusted. Accordingly, the specific gravity of the float means can be adjusted without stopping the operation of the hydro-hoist, that is, without exerting any influence on the overhaul processing operation.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawings which show, for the purpose of illustration only, one embodiment in accordance with the present invention.